


Mini McFly

by Eccentric_Calico



Category: Back to the Future (Movies)
Genre: Age Regression/De-Aging, Cutesy, Diapers, Fluff and Humor, Gen, No Angst
Language: English
Status: In-Progress
Published: 2019-04-28
Updated: 2019-04-28
Packaged: 2020-02-09 11:52:17
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,204
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18637588
Author URL: https://archiveofourown.org/users/Eccentric_Calico/pseuds/Eccentric_Calico
Summary: An accident in Doc's lab causes Marty to regress back to being a baby. As you can imagine, he's not happy about it. But thankfully he has people in his life who are more than happy to take care of him (as well as coo over how cute he is).





	Mini McFly

Marty groaned softly, slowly opening his eyes. He paused for a moment, wondering how he'd ended up on the floor, and why there was broken glass near him. Oh wait, that's right; He'd tripped. And somehow fell on and broke a wooden table on which Doc had placed several test tubes filled with various liquids. How had he even managed to do that?

"Marty!" Doc called, panic in his voice as he raced over to the dazed boy. "Are you alri-?!" He stopped, looking down at him. "Oh no."

Marty groaned again, lifting himself up with his arms. It was then he realized he was nude. Embarrassed, he tried to cover himself with the cloth that was currently covering him. Wait, this wasn't a cloth; It was... His t-shirt? But how could that be? It was so big! He looked down to see his jeans and underwear on the floor as well, both much bigger than they ought to be. Actually, now that he thought about it, the room seemed to have grown as well.

Einstein bounded over to Marty, barking happily. He was huge now, too!

"Doc, what the heck is going on?!" He asked. At least, he tried to ask that. However, what came out could only be described as infantile babble. Confused, he tried again. Yet again, babble. And was he hearing things, or was his voice more high-pitched? 

A chill running up his spine, he looked down at his hands, and his jaw dropped he saw just how small they were. The room hadn't grown, he'd shrunk!

"Oh, this is bad! Really, really bad!" Doc said, running his hands through his white hair.

"Doc!" Marty squeaked in distress. 

Doc scooped Marty up in his arms, keeping him wrapped in his too-big t-shirt. "My God, you're so small."

Marty made another noise of fright, wriggling slightly. What was going on?!

Doc shushed him quietly, taking a look at a cut on the boy's arm. Sure enough, there was some deep blue colored liquid where said cut was. "Not good," Doc said again, softer this time.

Marty whimpered loudly, getting frustrated.

Doc gently set Marty on a chair, and quickly retrieved a first aid kit. "Marty, remember that little project I mentioned earlier?" he asked, beginning to clean the cut.

Marty thought back to about a half hour earlier. Doc had said something about a new scientific breakthrough, but hadn't specified what it was. The boy nodded. "Yah."

"Well, it's a serum meant to physically regress people with cancer and other such illnesses so that they can either be treated at an earlier stage, or kept at a young age before they developed it, giving scientists more time to find cures. And, well, it seems to work better that I thought it might."

Marty's eyes widened. Wait, was Doc saying he was..?

"So, you're kind of a baby now," Doc told him.

"Baybee?!" Marty yelped, shocked.

"About nine to twelve months old, if I'm not mistaken," Doc nodded. "It seems that when you fell and cut your arm, some of the serum got in your blood."

This was far too heavy. Marty babbled fearfully, shaking a little.

"Now, I think I can whip up an antidote, but I have no idea how long it'll take; It could be days or even weeks."

Marty bit his lip with one of the few teeth he currently had. This couldn't be happening! He couldn't help but wonder what would happen if Doc couldn't turn him back to normal. What would his parents do? After all, they'd be worried sick if he didn't come home after a while. His poor mother would probably think he either ran away from home, or got kidnapped. His father might blame himself for whatever reason. And not to mention his brother and sister, who would be just as upset.

And then he remembered Jennifer. Oh God, Jennifer. She'd be devastated. And what if he ended up stuck like this forever, unable to ever be with her again?

Marty's lower lip wobbled as he thought about this possibility, tears now streaming down his face.

"Oh, Marty," Doc said in the most gentle voice he could manage. "It's gonna be alright; There's no need to cry."

But those words did nothing to soothe the small boy. Rather, upon realizing he was crying just like the little baby he currently was, he began bawling hard, his fear being the only thing he could focus on right now.

Slightly startled, Doc quickly picked Marty up, and began to gently pat his back. "Hey, it's okay, really! This isn't permanent!" He could just barely hear himself speak over the baby's wailing.

But still, Marty continued to sob, now also upset about seemingly not being able to act like an adult.

Doc thought for a moment, then softly shushed the boy. He rubbed Marty's back in a comforting manner, beginning to hum quietly in an effort to calm him.

Marty stopped mid-bawl, hiccupping a little as he was snapped out of his distress. He recognized that tune. It was a lullaby his mother used to sing to him. Whenever he was scared due to a nightmare, or just not feeling well, she'd hold him in her arms and sing until he fell asleep. He rested his head against Doc's chest, and listened quietly, not realizing he had started to smile.

As Doc continued to hum, he too smiled a little. Thank goodness Marty had calmed down; All that crying was beginning to hurt his ears. After a moment, he spoke to him once again. "Better, Marty?"

Marty nodded a little. "Yah," he cooed.

"Good," Doc breathed. "Now, while You're like this, you'll need a few things."

Marty nodded, and babbled about how he'd keep an eye on the lab while Doc aquired the items.

Doc paused for a second. Would it be okay to leave Marty by himself? He glanced around at all the various heavy objects, uncovered light sockets, and half finished inventions in the room, then shuddered slightly. "Oh no, I can't leave you here by yourself," Doc said, somewhat surprised that he even understood the baby talk.

"Wuh?" Marty asked, blinking his wide eyes.

"Well, you could hurt yourself! Besides, what if you needed something, and I wasn't here to care for you?"

Marty folded his arms. "Nuh baybee," he pouted.

"Yes, you are," Doc said firmly. "And you're coming with me."

Marty huffed indignantly, puffing out his little cheeks.

Doc chuckled a bit in spite of himself. "You look like a little hamster when you do that."

Marty whined quietly. "Buh."

 

Once they arrived at a local supermarket, Doc placed Marty in the child's seat of a shopping cart, still keeping the boy wrapped in the t-shirt.

"Down!" Marty squeaked, pointing at the floor. He was big enough to walk on his own! At least, he thought so.

"Don't be ridiculous; We can't risk you getting hurt walking or crawling by yourself," Doc told him. "Besides, you might end up losing what little clothing you have right now.."

"Bwut mwe big," Marty protested with a sad look in his eyes.

Doc sighed softly. "I know you don't like being this way, but you've got to try and accept it for the time being. I promise you'll be back to normal in due time," he said gently.

Marty's only response was a tiny whimper as he looked down at his lap. This just wasn't fair; Ever since he was a little kid, he couldn't wait to be an adult so he could be independent and do whatever he wanted. But now here he was, tiny, helpless, and not manly in the slightest. He was so lost in his negatively, he barely noticed that he and Doc were now in the baby aisle.

Doc quickly grabbed a couple of bottles, some formula and a few jars of baby food. He was certain Marty would protest against consuming it, but perhaps he could bribe the little guy somehow. He then turned back to his tiny friend, taking a tape measure out of his coat pocket, and proceeding to measure Marty's waist.

"Wuh?" Marty cooed, confused.

"Just have to make sure we get you the right sized diapers," Doc replied simply.

Marty groaned. Right. Of course he'd have to wear those. He hadn't had to since he finally stopped wetting the bed at age twelve, and he'd hoped to never even see another diaper again as long as he lived. He was close to bursting into frustrated tears when, for some reason, he stuck his thumb in his mouth. Not that he noticed right away, of course. Not until after he'd given it a few sucks.

His eyes widened as his thoughts skidded to a halt. What on earth was he doing? And why hadn't he noticed he was doing it? But more importantly, why did it feel good?

Noticing this bit of infantile behavior, Doc sneakily placed a couple of pacifiers into the shopping cart. "You know, you don't have to be ashamed of yourself for giving into any urges you may have in this state."

"Uh!" Marty said, shaking his head almost like a wet dog. He pouted yet again as he felt those damn tears starting to prick at his eyes. He turned his head away just in case he started openly crying again, not wanting to be seen like that for a second time. 

That was when he came face to face (nose to nose, even) with a friendly looking stuffed fox. Marty blinked in surprise, leaning back a little. He almost felt like the toy was staring at him. But still, it looked very cute. Wait, what was he thinking? He was a man, damn it! He wasn't into cute things, and he definitely wasn't into stuffed animals. After all, those were for babies. He crossed his arms, shutting his eyes tight with a "Hmph!"

But then he started to feel bad; What had this fox ever done to him? Maybe he shouldn't be so rude to it. He reluctantly opened his eyes to look at it once more, and began to notice just how soft it's orange fur looked. Curiously, he reached out to pet it, his face lighting up when he felt just how incredibly plush it was. He smiled, giggling in spite of himself as he pulled the stuffed animal off the shelf, holding it close to his chest as he kept petting it.

"Found something you like, have you?"

Startled, Marty froze, looking up at Doc with an embarrassed expression. 

Doc simply smiled at him, and ruffled his hair. "You know, you really are quite cute this way."

Marty stuck his tongue out, furrowing his brow. "Nuh."

"Oh, come on now; Aren't you tired of being so grumpy?" Doc teased.

"Nuh," Marty repeated.

Doc shook his head, chuckling quietly to himself as he pushed the shopping cart over to the baby section of the clothing aisle.

Marty groaned loudly. Was there no end to this humiliation?

"What? Would you prefer to just go naked?" Doc asked him.

Marty sighed and shook his head. "Nuuuuh..."

"There's a good boy."

Marty just rolled his eyes in response, clinging to the stuffed fox tightly.

As Doc picked out a couple of onesies for Marty (which thankfully were just plain, solid colored ones), a nearby middle-aged woman with curly hair who Marty immediately recognized as Jennifer's mother glanced over at the deaged boy, and smiled brightly. "Oh my goodness, look how cute you are!" she cooed, approaching him.

Marty suddenly found himself wishing he were invisible 

"Is he yours?" she asked Doc.

"Um, he's my...nephew," Doc lied.

"Oh, he's just darling," the woman crooned.

"Uh, y-yes, he-."

"Oh, Jenny! Come over here and take a look at this sweet little baby!"

Oh no.

Sure enough, Marty's girlfriend walked over from the women's clothing section, and looked down at him briefly before turning to her mother. 

"Mom, you can't keep coming up to everyone with a little-." She then glanced back at Marty, a shocked expression taking over her face.

Marty blushed a little, looking up at her with wide eyes.

_'Marty?'_ Jennifer mouthed as her mother continued to gush over how she 'could just eat him up with a wittle spoony-spoon'.

Marty nodded, motioning to Doc with his pudgy hand.

Jennifer glanced up at Doc, her mouth agape.

Doc put a finger to his lips, then pointing frantically to Jennifer's mother. 

"Oh! Mom, I forgot! I need, um... Bras," Jennifer lied, grabbing hold of her Mother's arm.

_'Smooth, Jen,'_ Marty thought to himself, shaking his head as he watched his girlfriend practically drag the older woman away.

Doc let out a sigh of relief. "That was a bit too close," he breathed. "We better get you out of here."

"You think?" Marty tried to say sarcastically. Of course, it came out more like "Abawawa?"

And with that, They quickly payed for everything (including Marty's fox), and hightailed it out of the store.

Marty couldn't help but suck his thumb nervously on the way back to Doc's place. _'Pleeease just let me be a grown-up by the end of the day.'_


End file.
